Note: Normally when adding a new custom element for the first time, you'd
want to add an HTML Import to ensure the component definition has been
loaded. However, this app template is already set up to lazy-load top
level views on-demand based on the route, so in this case you don't need
to add an import for your new <my-new-view> element.

The following code that came with the app template will ensure the
definition for each page has been loaded when the route changes. As
you can see, we followed a simple convention ('my-' + page + '.html')
importing the definition for each route, and you can adapt this code as you
like to handle more complex routing and lazy loading.

Register the page for the build

When you deploy your application to the web, you'll use the Polymer CLI
to prepare your files for deployment. Polymer CLI will need to know about any
demand-loaded fragments like the lazy-loaded view you just added.

Note: You only need to add files you will lazy load or import using the async
attribute to the fragments list. Any files that are imported using synchronous
<link rel="import"> tags should not be added to fragments.